Cylinder head for internal-combustion engines



Spt 9, 1952 E. P. PESCARA y2,509,805

CYLINDER HEAD FOR INTERNAL-COMBUSTION ENGINES Filed Aug. l, 1947 5 Sheets-Sheet l E? E (25, 133 I?? v E 34- l 234' H 3F 50 l?? INVENTUR 1 ENRxca Pn'rERns Pasen@ ATTU RN EYS Sept. 9, 19.52

E. P. PESCARA CYLINDER HEAD FOR INTERNAL-COMBUSTION ENGINES 5 Sheets-Sheet 2 Filed Aug. l, 1947 I INVENTUR l R www @wfg s N n R m m u o.

W l E Sept. 9, 1952 E, P, PESCARA 2,609,805

CYLINDER HEAD EOE INTERNAL- COMBUSTION ENGINES Y Filed Aug. 1Q 1947 3 sheets-sheet a' C fio O C) 5317 d j" "1 556 9N 5 ,"'j ,l "l," .EZ f Q9 333 3,52 (2X/, 321 fi 555 f o 519 E E26 x 250 @k O v *t-Mmf INVENTUR Emmen Pm'mns Pestman Patented Sept. 9, i952 CYLINDER HEAD Fon INTERNAL- f ooMBUs'rIoN ENGINES i Enrico Pateras Pescara, Cap dAntibes, France Application August 1, 1947, Serial No. 765,566

` In Spain June 10, 1943 o Section 1, Public Law 690, August 8, 1946 Patent expires June 10, 1963 9 Claims. 1 The present invention relates Vto the cylinder heads of internal combustion engines and more especially to those which are provided, in their end walls, with the seatsV of two distribution valves actuated, from a singlewcam-shaft, these Y engines being further characterized in thattlie stems ofsaid valves, located approximately in `a` transverse plane with respecttoV the axis of the engine are suitably inclined (or at least one of themis inclined) with respect to the axis of the corresponding cylinder, with a view to obtaininglarge section distribution orifices.

My invention is applicable both to engines made especially according 'to the features of said invention, and to engines of any existing type (explosion engines, Diesel engines, engines havingtheir valves housed in the cylinder head, in the cylinder block, having their valve system operated by a cam-shaft housed in the crankcase or in the cylinder head, engines fed with gasoline, with gas-oil, with gas, etc), the existing cylinder heads being in this case replaced by others made according to my invention.

The chief object of my invention, while ensuring a certain reduction of weight, volume and cost of said cylinder heads, is to increase the maximum specific power compatible with the general constructional `arrangements that are conventionally employed in industry.

It consists chiefly in the combination, in the u same cylinder head, of the three following characteristics: i

a. Inthe part corresponding to the valves, to their control mechanism and to the pipes, the cylinder head is made according to the usual standards of construction for engines having theirvalves disposed in the cylinder head and operated from a single cam-shaft, that Vis to say having an upper cooling water jacket around the seats of said valves, their guides and the pipes, the-Valve control mechanism being protected Aby a cover fixed to the cylinder head;

b. In the other regions, the cylinder head is of lowerheight than in said part and has the other characteristics of the conventional construction cylinder heads of engines having their valves disposed laterally in the cylinder-block, this cylinder head being not fitted with a cover in `said regions;

c. The ignition plug I or plugs are located wholly on the outside of the cylinder head cover and inside the region of lower height mentioned in paragraph (b), and open into the upper wall of' the combustion chamber, near the center thereof, preferably in an optimum position which .2 reduces to a minimum the path of travel of the flame during the ignition period and which proves to be very advantageous, both concerning accessibilityto said plugs and the cooling thereof. The arrangement of said low height region is further characterizedin that, on the one hand, it covers at least partly the combustion chambers of the cylinder head and, on the` other hand, it communicates with the outside through a discharge orice or channel of a shape such that water, oil, or any other liquid as may have entered thereinto, flow out freely.

In addition to this main feature, my invention may include the following other features to be used either together or separately. o

When double ignition is provided, in engines including one or several groups of cylinders in line, with two overhead valves having their axes in a transverse plane, the two ignition plugs of each cylinder are located symmetrically with respect to the axis of the combustion chamber and also with respect to said transverse plane of the two valves, which permits of obtaining a, perfect synchronizing, both from a geometrical and a thermal point of view in the propagation of lam from these sparking plugs.

`In order further to improve the position of the ignition plug or plugs, their axes are given an inclination 4such that the body of the plug is distant from 'the inlet and exhaust pipes, while, on the contrary, the ends of their elec,-` trodes are located as close as possible to the cen-` ter of the combustion chamber.

And, in the case of an engine having a double ignition, `I make use, for transmission of the cam-shaft drive to the inlet valve, of a bent rocker device, constituted by two levers fixedr to each other, and4 one of which receives the thrust from the cam while the other transmits this thrust to said valve, the second of said levers be-` ing located in a plane perpendicular to the plane that contains the axes of the two ignition plugs and being approximately midway between these two axes.

Preferred embodiments of my invention will be hereinafter described `with reference to the accompanying drawings, given merely by way of example and in which: I A' Fig. 1 is an elevational view, partly in section, of a cylinder headfor a block of two cylinders inline, according to my invention;

' Fig. 2 is a cross sectional view on the line A2`-2` of Fig. 3;

Fig. 3` is a top plan view of the structure of Fig.v 1, with the cover of the cylinder head removed;l

Fig. 6 is a planview of the cylinderhead of Fig.V

5 with the cover removed.

In the embodiment of Figs. 1 to 4, I have shown two cylinders IS and I I, a plane wall :I2 Ibeing adapted to receive the cylinder headgasket ,l

I associate with each of these cylinders (cylinder,

I being taken by way of example) a combustion chamber such as I4 in the top wallof which are located the seat of an inlet valve I5 the :axis .of which is inclined with respect to cylinder I0Y and the seat of an exhaust valve IBthe axisofwhich iS approximately parallel to that of cylinder-I0, these valve axes being disposed substantially-ina transverse plane with respect to the axis of the engine.

l,The movements ofvalvelIlB are controlled from a cam shaft l@mounted for instance inthe crankcase, 'through .a rod .Il which actuates .a bent rocker device pivoted on .aspindle '2U common 'to the control devices ofboth .of the cylinders Yliiland I.I .andwhich will 'bemore .explicitly referredto hereinafter.

.The .opening and closing .or .exhaust valve V'I'S are ensured, .from the .same cam-shaft C jthat controls valve I5, through rod I9 and .rocker means 24 pivoted on aspindle'2 I.

AIn .cylinder I.I Athe Vparts `of fthe controlmechanismare identical .to and symmetrical wththose above described, .and .they .are designated onithe drawings by the .same reference `numerals .increased by .Idil .(rod .I.I l, l'l'rocker arm 'I 2fl,v e'tc.)..

`The 'ignition plugs of chamber I4 that porrerspond Lto cylinder ,I0 4are `.located at 22., 23.in `the case `of double ignition, and only voneio'f them is provided in thecaseof asimpleignition.

.As it vcan be seen from-.the drawings,.said.plugs 22, 2'3, .the axes of which are .advantageously inclined, open into .the upper wall of combustion chamber Ibetween theseats of valves 115 vand I 6 and in the vicinity ofthe .centerof `this chamber.

The -above mentioned inlet. vrocker .device includes a lever .36,actuated by rod I7, .asleeve '.'s-I journalled Von .spindle "fl and another V'lever I8 which actuates inlet valvev I5. .It .shouldbe noted thatsaid lever Iis located ina plane perpendicular .to `that determined by the l.axes .ofplugs 22 and 23 and is at .equal distancebetween them.

An identical arrangement is `used for cylinder II,\where .the ignitionplugs are I'22,.I23 andthe inlet rocker arm I 3I3,'I3TI, IHS. y

The valve .control .mechanism constituted-by theabove indicated parts -and in particular bythe four rockermeans BS- BI-IB, 'I35-I3I-II8, 24 and |24 and their spindles 2.53, 2| .and I2I are proe tected by a common cover '2 5 of particular shape which covers allthepart of theoylinder/head that includes `valves I5, .'I I 5, I5, I It, their control means I1II'I, IS, IIS, 3B-Sl-I8, ISG--I'S'ITIHL 24, |24, inletpipes 21, IZ'I, exhaust pipes suchas 28 and, generallyv speaking,.all'the water jacket 25J-that surrounds the valveguides, such asS and SI and springs 32, |32, and 33; I33.

The gasket 26 of cover25 ,iirstgpasses around thesparking plug 22 of cylinder IG, thenaround the spring 32 of valve Iand around .thesecond plug 2 3, .following the same outline around .the

corresponding parts located above cylinder II..

Between inlet pipes 27, 121 there isle'fta free interval'.

Thus, the non-covered portion of the cylinder head, i. e. that on the outside of cover 25 includes:

l. On the right and on the left of this cover, two regions 34, I34 in which the sparking plugs 22, I22 are screwed, 2. vAt lthe center, a :region r35 kin which are screwed sparkingplugs 23, |23.

This non-covered portion of the cylinder head,

including said regions 34, |34, 35, which extends .asfar-as onesde wall of the cylinder block, has

itsj-.topfface at a level lower than the portion located under cover 25, which corresponds to water `jacket I29. Consequently, region 35 constitutes a :hollow-in the vtop face of the cylinder head. But

waterfoil, or any other liquid as may have entered this hollow, is allowed to flow out through intervalll, 'which extends down to the level of vthebottom-of hollow 35.

Oficourse, the construction which has just been described in the case oftwo cylinders in line such as II), I I, may be .repeated twicel `thricefand as much :as four times, .according as the' .rangingy includes four,.six .or eightc-ylinders. I .would thus provide Aa number of ,elementary .cylinder yheads equal to the number of pairs of cylinders inthe engine. ,'But such` an arrangement, which consists in treating two'by two the adjacentcylindersand which may have advantages in certain casearfor instanceiin engines of Vlarge-unitary cylinder capacity, must not be. considered.as.an.essentialfreature of my 'invention since, as it will .beeasily understood, the latter might as well be applied to engines having more `thanfour 4cylinders in line with a `single cylinder ihead or.=at.least .alcylinder head divided in a.manner.suitably-adapted to the division of :the cylinder vheadicover.

' If, .for instance, itis .desired to .provide-awk inder head for an engine 'having .four-cylinders in line, `I make for ,instance useo'f the arrangement of niemand-6..

The various parts 'to beincludedinfthe cylinder head having been 'sufficiently ldescribed I above, Vit suffices now to indicate the chief pieces Vofgthis new assembly, to wit: the vcylinders (only two of which, I- and '2 I'I .are ,shox/vnl., Athe A.plane wall 2 I2 forjgasket 2I3, the combustion chambers :ZI-.4 and 3M, the inlet valves '.3I5, the -exhaust Yvalves SI5, the control Yrods AE'II and '3I.`I.,the exhaust rocker 'arm axes .22.5 and 321i, .andthe exhaust rocker support'Z' I A The combustion chamber, in 'this case,.is 13110.- vided with only one ignition plug2'22, '322'. L'Ihe inlet valve rocker device is simplefand constituted by a single llever 236, 335.sleeve '23733Lfbeing journalied on spindle 22B which vris common ,to the group oftwo cylinders that isshown. Y

The cylinder head cover 225, o'f `particular shape, surrounds, `as vin the above described .example, the ywhole of rthe valve control parts and 1s-common'to the'four cylinders ,of the engine,'the part that is not shown being symmetrical with respect to the half that is visible on Figf.

Thegasket 226 of cover 225 passes `iirst around theignitionplug 222 of cylinder ZISL'then around the spring 232 of the linlet valve of cylinder 121,10 and also around the-springs of tl? e-success'iveiinlet` valves` such as the spring '332 that .corresponds Ito-valve 3515,. etc., as :iaras the vend o' the cylinder block. (not shown). I

Thence, the gesl-:et in question ,passes around the `springs of the various exhaust valves tand the plugs corresponding .to each cylinder.

In theY centralportion, it-will be -noted that Ithis gasketZSS must pass .around .botlrplugSZ-. and plug 2.2, .thus .iorming va .chamber .closed over portion of the combustion chamber. -rangement of the plugs permits of increasing to its whole periphery, with the exception of a passage corresponding to a kind of outlet channel -After plug 322, which corresponds to cylinder 2l 1,. the gasket nishes its circuit by passing around the springs of the exhaust valves.

In this way, there remains on the outside of cover 222:

.1. `On the right and on the left thereof, two regions of low height such as 234 (the other one, which is symmetrical therewith being not shown) in' 'which theplugs of the end cylinders such as 222are screwed and,

` 2. In the central portion, a region 235 in which arescrewed the plugs 322 and 422 of the central cylinders, this last region communicating with the outside through discharge channel 250.

As, on the inside of the cylinder head, in all the portion thereof that corresponds to these regions 235, 234 and those symmetrical therewith and not shown, there is no part or conduit, the height of this cylinder head can be reduced in these regions to that of the water jacket necessary for the cooling of the combustion chambers that this jacket covers partly.

Such` a construction further permits of reducing the weight and the volume of the cylinder head, while the plugs are located within easy reach, are well cooled and in the mostl adequate This ar- `which have combustion chambers of large volume and also of poor thermal efficiency when the plug or plugs are disposed far from the positions corresponding to the minimum path of travel o1 the ame.

This advantage is further increased when these engines of large cylinder capacity are intended to be fed with a gas the combustion of which is very slow. o o

It will be further understood that, in the case of double ignition, the symmetrical position of the two plugs permits of ensuring a better synchronizing of `the propagation of the names that are produced at each or these` plugs. This result .is particularly interesting since, when synchronizing is not ensured, double ignition gives no advantage and, on the contrary, involves may drawbacks.

i In` engines including one or several groups of cylinders in line, `it seems possible, at first sight, to obtain an apparent symmetry when the valves are disposed transversely to the axis or the engine, by placing a plug at either end of the transgeometrical one because the thermal conditions vary considerably from the region of the combustion chamber that corresponds to the exhaust valve to the much cooler region around `theinlet valve, and, on the other hand, it is not possible to place the plugs in the lateral wall located between two consecutive cylinders of a group of cylinders in line.

It follows that, in engines of the kind in question, the only solution for complying both with geometrical symmetry and with thermal symmetry while remaining inside acceptable` conditions of accessibility and cooling, is the solution given by the present invention.

However, the above described arrangement of the plugs is not to be mistaken for the one, already known in the art, which consists in hav- "ing said Vignition means opening into the upper wall of the combustion chamber and in locating them in the cylinder head `which further contains the valve Vseats because, according to this known arrangement, the plugs are disposed at the bottom of a tube which extends, over itsI whole height, through the cylinder head cover, which tube also acts eventually as a means for fixing or removing these plugs, in View of the great diiculty of reaching them.

Independently of this drawback, this known arrangement has many others: multiplicity of oil leaks, bad cooling, dicult insulation and therefore necessity of costly and little reliable devices, etc., to which drawbacks the invention remedies fully.

Finally, it should also be noted that the inclination of the plug or plugs with respect to each other permits of further improving their position in the combustion chamber by placing them closerto the center of the latter, while it renders the machining of the cylinder head easier.

In a general manner, while I have,in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangements, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims. What I claim is:

1. In an internal combustion engine including a block of at least two cylinders in line, a cylinder head-forming a combustion chamber for each of said cylinders, the top walls of eachof said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said seats, respectively, the stems of said two valves being located in a plane perpendicular to the plane of the axes of said cylinders and at least one of these two stems being inclined with respect to the axis of the correspeonding cylinder, inlet and exhaust pipes leading to saidseats, respectively, rocker arm means located above said cylinder head for operating said valves,` means located Wholly on one side of the plane passing through the axes of said cylinders for driving said rocker arm means, a cover for protecting said rocker arm means carried by said cylinder head extending exclusively over` the portion thereof corresponding to said valves, said rocker arm means and said driving means, the non-covered portions of said cylinder head being of lower height than the portion thereof tted with said cover and extending as far as the side wall of said cylinder block located on the other side of the plane of the cylinder axes from said driving means, and at least one ignition plug mounted in said non-covered portions of the cylinder head and opening into said combustion chamber near the center thereof.

2. In an internal combustion engine including a block of at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the top walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet'l valve and an exhaust valve adapted to cooperate `with said seats, respectively, the stems of. said two valves being located in a plane perpendicular to the plane of the axes 0f said cylinders and at least one of these two stems being inclined with respect to the axis of the corresponding cylinder,

.inlet and `exhaust pipes leading tosaid seats, `respectively, rocker arm means located .abovesaid rcylinder head for .operating said valves, means vlocated wholly onlone side of fthe .plane passing throughrthe axes of said cylinders for driving said rocker arm .means a cover tor protecting `said rocker Yarm means carried by .said cylinder head extending exclusively over the portion thereof corresponding to said valves, said .rocker arm means and said driving means, the non-'covered portions of said cylinder head Ybeing of .lower height than `the portion thereof v'iitted with vsaid coverand extending as faras the side wall of said cylinder block .located on Vthe other sidecf the pla-ne of the cylinder axes from said driving means, and twoignition plugs for each :cylinder mounted in said'non-covered portions of `the cyln .inder head so as to open into `said combustion chamber near the .center thereof, saidplugs being disposed'symmetrically with respect both tothe axis of said cylinder and tothe vtransverse*plane of the stems of the two valves of said cylinder;

3. In an internal combustion engine including a block `ofat vleast two cylinders in line, a cylinder -head'forrning a combustion .chamber for each of said cylinders, the top walls 'of each of said cha-1n- :bers being Vprovided with an inlet valve seat and an exhaust valve'seat, an inlet valve and an exhaust y.valve adapted to 'cooperate with said seats, respectively, the stems of saidtwo Vvalves being located in a plane perpendicularwto the'plane of the axes of said cylinders and iat leastJ Vone of these two stems being inclinedfwith respect to the axis ofthe ,corresponding cylinder, 'inletrand exhaust pipes leading 'to said seats, respectively,

rocker arm means located `above said cylinder head for operating said valves, .means located whollyV on one'side ci theplane passing through `the axes of said cylinders for driving said rocker arm Vmeans, a cover for protecting said rocker v.

arm means carried by said'cylinder 4head extending exclusively over the portion thereof corresponding to said valves, said rocker arm means and said driving means, the non-covered portions of said cylinder head being `of 'lower heightthan the portion thereof fitted with said cover-.and extending `as far as the side wall of said cylinder block located on the other side of the plane-ofthe cylinder axes from said driving means, vand at least one ignition plug mounted in said non-covered portions of the cylinder head and opening into said'combustion chamber 'near the center thereof, said plug yhaving its axis inclined with respect vto the corresponding cylinder axis so as tohave .the -plug body at the maximum distance from said pipes and its electrode close to the center of the combustion chamber.

4.111 an internal combustion engine including a .block of at least two cylinders in line, a cylin- .der head forming a combustion chamber for each .of saidrcylinders, the top Walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valveand an exhaust valve adapted to cooperate with said seats, respectively, the stems or said two valves being located in a plane perpendicular to the plane of the axes of said cylinders andat least one of these two stems being inclined withrespect to the axis of the corresponding cylinder, inlet and exhaust pipes leading to said seats, respectively, rocker arm means located above .said cylinder head for operating said valves, means Alocated wholly on one side of the plane passing through the axes .of said cylinders for driving said .rocker arm means, a cover .for protecting said rocker .arm Ameans carried by said cylinder .head

4extending exclusively overY the portion thereof corresponding to said valves, said rocker .arm meansand'said 'driving means, the non-'covered portions of said rcylinder head being 'of lower height than the portion thereof fitted with said cover and extendingas far as the side wall of said cylinder block located on the other side of the plane of the cylinder axes `from said driving vineansVand two ignition plugs for each cylinder mounted in `said non-covered portions of the cylinder head so as to open into said combustion chamber near the center thereof, vsaid plugs being disposed symmetrically with respect both to ythe laxisof said cylinder and .to the transverse plane of the stems of the two Valves of said cylinder, said plugs having their axes inclined -withrespect to the corresponding cylinder axis so as to have each plug body at the maximum distance from said pipes and its electrode close to the center-of the combustion chamber.

5. In an internal combustion engine including a block of at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the top walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said seats, respectively, the stems of said two'valves being located in a plane perpendicular to Vthe plane of the axes of said cylinders and at least one of these two stems being inclined with respect tothe axis of the corresponding cylinder, inlet and exhaust pipes leading to said seats, respectively, means located above said cylinder head for operating said valves, a cover carried by said cylinder head extending exclusively over the portion thereof corresponding to said valves and said valve operating means, the non-covered portions of said cylinder head being of lower height than the portion thereof tted with said cover and extending as far as one side wall of said cylinder block, two ignition plugs for each cylinder mounted in said non-covered portions of the cylinder head so as to open into said combustion chamber near the center thereof, said plugs being disposed symmetrically with respect both to the axis of said cylinder and to the transverse plane of the stems of the two valves of said cylinder, a single cam-shaft for driving said valve operating means located on one side of the plane passing through the axes of said cylinders,'said valve operating means including a part pivoted to said cylinder head aboutV an axis perpendicular to the transverse planes containing each the stems of the two valves of each cylinder, tworocker arm elements rigid with said part, operatively connected with said cam-shaft respectively, and two rocker arm elements, also rigid with said part and at right angles to the pivot axis thereof adapted to cooperate each with the inlet valve of one of said two cylinders respectively for .controlling it, said .second mentioned rocker arm elements being each located at mid-distance from the axes ofthe ignition plugs of the corresponding cylinder.

6. In an internal combustion engine including a block of .at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the tcp walls of each of said chambers being provided with an inlet valveseat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said seats, respectively, the stems of said `two valves being located in a plane perpendicular to the plane of the axes of said cylinders and at least one of these two stems being inclined with respect to the axis of the corresponding cylinder, inlet and exhaust pipes leading to said seats, respectively, means located above said cylinder head for operating said valves, a cover carried by said cylinder head extending exclusively over the portion thereof corresponding to said valves and said valve operating means, the non-covered portions of said cylinder head being of lower height than the portion thereof itted with said cover and extending as far as one side wall of said cylinder block, two ignition plugs for each cylinder mounted in said non-covered portions of the cylinder head so as to open into said combustion chamber near the center thereof, said plugs being disposed symmetrically with respect both to the axis of said cylinder and to the transverse plane of the stems of the two valves of said cylinder, said plugs having their axes inclined with respect to the corresponding cylinder axis so as to have each plug body at the maximum distance from said pipes and its electrode close to the center of the combustion chamber, a single camshaft for driving said valve operating means located on one side of the plane passing through the axes of said cylinders, said valve operating means including a part pivoted to said cylinder head about an axis perpendicular to the transverse planes containing each the stems of the two valves of each cylinder, two rocker arm elements rigid with said part, operatively connected with said cam-shaft respectively, and two rocker arm elements, also rigid with said part and at right angles to the pivot axis thereof adapted to cooperate each with the inlet valve of one of said two cylinders respectively for controlling it, said second mentioned rocker arm elements being each located at mid-distance from the axes of the ignition plugs of the corresponding cylinder.

7. In an internal combustion engine including a block of at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the top walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said seats, respectively, the stems of said two valves being located in a plane perpendicular to the plane of the axes of said cylinders and at least one of these two stems being inclined with respect to the axis of the corresponding cylinder, rocker arm means located above said cylinder head for operating said valves, means located wholly on one side of the plane passing through the axes of said cylinders for driving all of said valve operating means, inlet and exhaust pipes leading to said seats, respectively, cooling Water jacket means surrounding said valve seats and said pipes included in said cylinder, a cover for protecting said rocker arm means carried by said cylinder head extending exclusively over the portion thereof corresponding t said valves, said rocker arm means and said driving means, the non-covered portions of said cylinder head being of lower height than the portion thereof tted with said cover and extending as far as the side wall of said cylinder block located on the other side of the plane of the cylinder axes from said driving means, and at least one ignition plug mounted in said non-covered portions of the cylinder head and opening into said combustion chamber near the center thereof.

8. In an internal combustion engine including a block of at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the top walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said l seats, respectively, the stems of said two valves being located in a plane perpendicular to the plane of the axes of said cylinders and at least one of these two stems being inclined with respect to the axis of the corresponding cylinder, inlet and exhaust pipes leading to said seats, respectively, rocker arm means located above said cylinder head for operating said valves, means located wholly on one side of the plane passing through the axesof said cylinders for driving said rocker arm means, a cover for protecting said rocker arm means carried by said cylinder head extending exclusively over the portion thereof corresponding to said valves, said rocker arm means and said driving means, the noncovered portions of said cylinder head being of lower height than the portion thereof tted with said cover and extending as far as one side wall of said cylinder block, and at least one ignition plug mounted in said non-covered portions of the cylinder head and opening into said combustion chamber near the center thereof.

9. In an internal combustion engine, a block of at least two cylinders in line, a cylinder head forming a combustion chamber for each of said cylinders, the top Walls of each of said chambers being provided with an inlet valve seat and an exhaust valve seat, an inlet valve and an exhaust valve adapted to cooperate with said seats,

respectively, the stems of said two valves being located in a plane perpendicular to the plane of the axes of said cylinders and at least one of these two stems being inclined with respect to the axis of the corresponding cylinder, rocker arm means located above said cylinder head for operating said valves, means located wholly on one side of the plane passing through the axes of said cylinders for driving all of said valve operating means, inlet and exhaust pipes leading to said seats, respectively, cooling fwater jacket means surrounding said valve seats and said pipes included in said cylinder, a cover for protecting said rocker arm means carried by said cylinder head extending exclusively over the portion thereof corresponding to said valves, said rocker arm means and said driving means, the noncovered portions of said cylinder head being of lower height than the portion thereof fitted with said cover and extending as far as one side wall of said cylinder block, and at least one ignition plug mounted in said non-covered portions of the cylinder head and opening into said combustion chamber near the center thereof.

ENRICO PATERAS PESCARA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,401,210 Willgoos May 28, 1946 2,421,510 Leek et al. June 3, 1947 FOREIGN PATENTS Number Country Date 224,822 Great Britain Nov. 20, 1924 559,864 Germany Sept. 24, 1932 217,037 Switzerland Jan. 16, 1942 

